Advanced combustion strategies for gasoline engines in the future depend on the existence of accurate pressure feedback from each combustion cylinder during the entire cycle (compression-combustion-exhaust cycle). These strategies may or may not include Homogeneous Charge Compression Ignition (HCCI) combustion, and can result in high pressure release rates which require fast and accurate pressure response.
A piezo-resistive pressure-measuring plug is known from EP2138819A1. The pressure-measuring plug comprises a very small sensing element that can be placed near the combustion side and therefore a very high bandwidth sensor is feasible. By means of bonding wires, the sensing elements are electrically coupled with sensor electronics on a printed wiring board (PWB) which is located in the plug body. The sensor electronics is arranged to measure a resistance change of the piezo-resistive elements mounted on a sensing structure and to generate a conditioned measurement signal therefrom. Connector terminals are arranged in a housing which is attached to the plug body. The connector terminals are electrically coupled via the sensor electronics to the sensing element arranged in the plug body. The document does not disclose how to obtain a reliable electrical connection between the piezo-resistive elements arranged in the plug body and the electronic parts outside the plug body. The electrical connection has to withstand the high temperature and vibrations typical to an environment of an internal combustion engine.